Billiard training aid



FIG. 1 is a perspective view of a billiard training aid showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a front elevational view thereof; and

FIG. 6 is a rear elevational view thereof.

The broken line showing of golf ball in FIG. 5 is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a billiard training aid, as shown and described. 